/** @file
 *
 * Structures that most TVB users should not be accessing directly.
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#ifndef __TVBUFF_INT_H__
#define __TVBUFF_INT_H__

struct tvbuff;

struct tvb_ops {
    size_t tvb_size;
    void (*tvb_free)(struct tvbuff *tvb);
    unsigned (*tvb_offset)(const struct tvbuff *tvb, unsigned counter);
    const uint8_t *(*tvb_get_ptr)(struct tvbuff *tvb, unsigned abs_offset, unsigned abs_length);
    void *(*tvb_memcpy)(struct tvbuff *tvb, void *target, unsigned offset, unsigned length);

    int (*tvb_find_uint8)(tvbuff_t *tvb, unsigned abs_offset, unsigned limit, uint8_t needle);
//    int (*tvb_ws_mempbrk_pattern_uint8)(tvbuff_t *tvb, unsigned abs_offset, unsigned limit, const ws_mempbrk_pattern* pattern, unsigned char *found_needle);

    tvbuff_t *(*tvb_clone)(tvbuff_t *tvb, unsigned abs_offset, unsigned abs_length);
};

/*
 * Tvbuff flags.
 */
#define TVBUFF_FRAGMENT        0x00000001    /* this is a fragment */

struct tvbuff {
    /* Doubly linked list pointers */
    tvbuff_t                *next;

    /* Record-keeping */
    const struct tvb_ops   *ops;
    bool        initialized;
    unsigned            flags;
    struct tvbuff        *ds_tvb;  /**< data source top-level tvbuff */

    /** Pointer to the data for this tvbuff.
     * It might be null, which either means that 1) it's a
     * zero-length tvbuff or 2) the tvbuff was lazily
     * constructed, so that we don't allocate a buffer of
     * backing data and fill it in unless we need that
     * data, e.g. when tvb_get_ptr() is called.
     */
    const uint8_t        *real_data;

    /** Amount of data that's available from the capture
     * file.  This is the length of virtual buffer (and/or
     * real_data).  It may be less than the reported
     * length if this is from a packet that was cut short
     * by the capture process.
     *
     * This must never be > reported_length or contained_length. */
    unsigned            length;

    /** Amount of data that was reported as being in
     * the packet or other data that this represents.
     * As indicated above, it may be greater than the
     * amount of data that's available. */
    unsigned            reported_length;

    /** If this was extracted from a parent tvbuff,
     * this is the amount of extracted data that
     * was reported as being in the parent tvbuff;
     * if this represents a blob of data in that
     * tvbuff that has a length specified by data
     * in that tvbuff, it might be greater than
     * the amount of data that was actually there
     * to extract, so it could be greater than
     * reported_length.
     *
     * If this wasn't extracted from a parent tvbuff,
     * this is the same as reported_length.
     *
     * This must never be > reported_length. */
    unsigned            contained_length;

    /* Offset from beginning of first "real" tvbuff. */
    int            raw_offset;
};

tvbuff_t *tvb_new(const struct tvb_ops *ops);

tvbuff_t *tvb_new_proxy(tvbuff_t *backing);

void tvb_add_to_chain(tvbuff_t *parent, tvbuff_t *child);

unsigned tvb_offset_from_real_beginning_counter(const tvbuff_t *tvb, const unsigned counter);

void tvb_check_offset_length(const tvbuff_t *tvb, const int offset, int const length_val, unsigned *offset_ptr, unsigned *length_ptr);

#endif
